Variable Capacity Compressors
Variable capacity compressors can vary the volume of refrigerant depending on the demands of the system. The demands of the system are sensed by the pressure of the refrigerant coming out of the evaporator. The demand is the amount of heat transferred to the refrigerant. This increase in temperature will affect the pressure that will eventually enter the inlet of the compressor housing.The minimum displacement of a variable type compressor is about 10cm3 and is not zero because the refrigerant carries the lubricant for the compressor which would cause damage if no refrigerant was present inside the compressor while it was operating. Variable capacity compressors greatly reduce the amount of on/off cycles that non-variable capacity compressors are subjected to. This reduces noise from the clicking of the magnetic clutch, increases fuel efficiency through variable loading of the system and reduces the wear of the magnetic clutch plate.Variable types of compressor generally differ from the non-variable type due to the addition of a control valve.The control valve is used to vary the displacement of the compressor to match the demands of the system.